If you've put on a few pounds, the most obvious culprits are your doughnut addiction or sedentary lifestyle, but Emory University marketing professor Ryan Hamilton and several co-authors say that multitasking might be a contributing factor. Frequently shifting focus or to different types of tasks depletes the mental resources you need for self-control -- including the self-control to say no to one more doughnut.

To prove this idea, the research team asked some volunteers to switch between very different tasks and some other, bi-lingual volunteers to switch between languages, then tested their self-control. The results revealed that "if you switch mindsets you are worse at self regulation," Hamilton said. And among the consequences of impaired self-regulation is the inability to control your cravings.

But it's not only your waistline that can suffer from the mental fatigue that comes from constantly switching tasks, the quality of your work can also decline, according to Hamilton, who says multi-tasking,

makes you less able to endure tedious or uninteresting tasks so you can't concentrate as well--From a business perspective, it's probably easiest to say employers should care about this because it can influence the performance of their employees.

Hamilton is probably right that your employer is going to be more interested in your argument against multitasking if you cite the possible negative consequences for concentration and quality of work rather than if the fact that it'll make it harder for you to get into shape for the beach this summer. And I am sure the findings that switching modes of thought depletes self-control are correct, but is the news about multitasking and diet really any help to anyone?

First off, you might be able to cut back, but in a world with email, smartphones, pinging instant messages, chatty co-workers and needy offspring, is anyone going to be able to quit multitasking completely, no matter how harmful scientists find it to be? You'd have to entirely revamp your lifestyle to stop so the level of harm really needs to justify the effort. And second, people trying to drop a few pounds and get healthy already have so many bits of celebrity "wisdom" and weight loss trends confusing the simple reality that eating less and sweating more is the way to go. Will one more excuse really make anyone's life any better?